1. Field of the Invention
This invention relates to a moving image communication evaluation system and a moving image communication evaluation method and more particularly to a moving image communication evaluation system and a moving image communication evaluation method for evaluating a response time of moving image display to a moving image request in moving image distribution service on a network.
2. Description of the Related Art
In recent years, a moving image service industry of distributing moving images on a communication network has become prevalent. In the moving image service industry, the degree of satisfaction of the user requesting a moving image is important and the response time to the user's request is also one of the factors for determining the quality in the moving image service. Since moving image communication tends to take much time in processing of transmission, reception, decoding, display, etc., as compared with voice communication and data a communication, it is important to monitor and manage the response time to the user's request.
Hitherto, for example, a moving image communication evaluation system as described in JP-A-7-121459 and that as described in JP-A-5-336209 have been known as systems for measuring and evaluating the response time when a moving image is transmitted and received between communication terminals via a network. A configuration example of a moving image communication evaluation system in a related art shown in FIG. 4 is provided by simplifying the configuration described in JP-A-7-121459, wherein a relay node 33 comprising a response time measurement section 6 and a relay node 34 comprising a response time measurement section 7 are connected to a network 10 and communication terminals 31 and 32 are connected to the relay nodes 33 and 34 respectively.
When a transmission request packet addressed to the communication terminal 32 is transmitted from the communication terminal 31 to the relay node 33, the relay node 33 passes the transmission request packet to the network 10. The communication terminal 32 receives the transmission request packet transmitted on the network 10 via the relay node 34 and transmits, for example, a reply packet addressed to the communication terminal 31 in response to the request in the transmission request packet. The reply packet is transmitted through the relay node 34, the network 10, and the relay node 33 and is received at the communication terminal 31.
The response time measurement section 6 in the relay node 33 measures the difference between the time at which the relay node 33 passes the transmission request packet and the time at which the relay node 33 passes the reply packet as the response time. In contrast, if a transmission request packet addressed to the communication terminal 31 is transmitted from the communication terminal 32 and a reply packet addressed to the communication terminal 32 is transmitted from the communication terminal 31, the response time measurement section 7 in the relay node 34 measures the difference between the time at which the relay node 34 passes the transmission request packet and the time at which the relay node 34 passes the reply packet as the response time.
A configuration example of a moving image communication evaluation system in a related art shown in FIG. 5 is provided by simplifying the configuration described in JP-A-5-336209, wherein a communication terminal 35 comprising a response time measurement section 8 and a communication terminal 36 comprising a response time measurement section 9 are connected to a network 10. When a transmission request packet is transmitted from the communication terminal 35 through the network 10 to the communication terminal 36, the communication terminal 36 receives the transmission request packet and transmits, for example, a reply packet through the network 10 to the communication terminal 35 in response to the request in the transmission request packet. The communication terminal 35 receives the reply packet.
The response time measurement section 8 in the communication terminal 35 measures the difference between the time at which the communication terminal 35 transmits the transmission request packet and the time at which the communication terminal 35 receives the reply packet as the response time. In contrast, if a transmission request packet is transmitted from the communication terminal 36 to the communication terminal 35 and a reply packet is transmitted from the communication terminal 35 to the communication terminal 36, the response time measurement section 9 in the communication terminal 36 measures the difference between the time at which the communication terminal 36 transmits the transmission request packet and the time at which the communication terminal 36 receives the reply packet as the response time.
However, if importance is placed on the degree of satisfaction of the user in the moving image service, the response time that the user feels, namely, the time interval between the instant at which the user performs operation of making a moving image request and the instant at which moving image display is changed as requested by the user must be measured, monitored, and managed. For example, in the moving image communication evaluation system in the related art as shown in FIG. 4, if a moving image transmission request packet is transmitted from the communication terminal 31, only the time of “the packet traveling time between the relay node 33 connected to the communication terminal 31 and the communication terminal 32 transmitting the requested moving image” plus “the request processing time of the communication terminal 32 transmitting the requested moving image” is measured. In the moving image communication evaluation system in the related art as shown in FIG. 5, only the time of “the packet traveling time between the communication terminals” plus “the request processing time of the communication terminal transmitting the requested moving image” is measured. Thus, the moving image communication evaluation systems in the related arts cannot measure or evaluate the response time that the user feels.
Various types of communication networks become widespread; for example, the Internet, LANs (local area networks), public telephone networks, cable television networks, optical fiber networks, cellular mobile telephone networks, satellite communication networks, etc., can be used. Moreover, among the various communication networks, a heterogeneous network where different types of networks are interconnected is often used between communication terminals and a large number of types of communication protocols are actually used. Further, the types of networks to which terminals that can access one server are directly connected are various. Thus, the moving image communication evaluation system in the related art as shown in FIG. 4 involves a large number of types of relay nodes 33 and 34 in which the response time measurement sections 6 and 7 are to be imbedded for which design, development, and evaluation must be carried out separately.
The communication networks are advancing rapidly and enlargement of a geographic area, change in network topology, improvement in, new installation of, and change in methods, systems, apparatus, protocols, terminals, and service, and the like are executed from day to day. Thus, in the moving image communication evaluation system in the related art as shown in FIG. 4, whenever the relay node 33, 34 is improved or newly installed, the response time measurement section 6, 7 must be improved or installed and evaluated accordingly.
Further, in the cellular mobile telephone networks, the satellite communication networks, the wireless LANs, etc., the geographical positions of the communication terminals change frequently and the radio transmission characteristics change in quality, namely, are good or bad from time to time, so that the transmission error occurrence frequency grows and in the Internet, packet discharge at heavy traffic hours occurs frequently, thus a moving image display error often occurs. A moving image communication evaluation system that can measure and evaluate the response time that the user feels if such a display screen error occurs is demanded. For the moving image service dealers and managers, the response time that the user feels is at stake and therefore a moving image server terminal does not require a response time measurement section. Thus, such a moving image communication evaluation system wherein only user terminals are provided each with a response time measurement section is demanded.